This invention relates to novel scavengers and the use thereof. In particular, this invention relates to high capacity macroreticulate polymer scavengers comprising a macroreticulate polymer backbone having a plurality of pendant metallated functionalities and their use to remove oxidants and Lewis acids from inert fluids including both liquids and gases.
In numerous products and processes the purity of fluids is of critical importance. Often, the presence of even small amounts of Lewis acid or oxidant impurities will dramatically reduce the utility of a fluid. Consequently, there is a continuing need for new and better ways of purifying such fluids.
Among the known methods for purification of inert fluids is the use of scavengers. With this method, a fluid is passed over a scavenger, as for example passed through a bed or column containing the scavenger, and the scavenger reacts with and removes impurities without affecting the fluid itself.
Among the properties desired in a good scavenger are removal of a wide variety of impurities, a low level of impurities left in the fluid after treatment with the scavenger, and a high capacity for reaction with and removal of impurities. In other words, a small amount of scavenger should effectively reduce the amounts of a wide variety of impurities to a low level. Furthermore, it is desired that a scavenger be effective not only when swollen by the liquid to be purified, but that it be effective with liquids that cannot swell the scavenger, and gases. In some embodiments it is also desired that the scavenger have uniform loading, i.e., some of its reactive sites should not be more reactive than others. Where a scavenger does not have uniform loading it does not behave consistently throughout its lifetime, thereby making it difficult to predict how the scavenger will perform at any particular time. It is also desired that the scavenger have good thermal stability. Finally, it is desired that the scavenger change color upon reaction with impurities, e.g., change from an intensely colored to a colorless state as it becomes exhausted, thereby indicating when the scavenger needs to be replaced.
U.S. Pat. Nos. 3,079,428 and 3,316,223 teach purifying organic liquids of acidic impurities by contacting the liquids with an insoluble polymeric anionic scavenger material.
Chemical and Engineering News, Nov. 15, 1982, p. 15 discloses that functionalized poly(styrene-divinylbenzene), including lithiated poly(styrene-divinylbenzene), may be used as a catalyst support. Taylor, Macromolecules, 14, (1981), pp. 135-138, discloses the treatment of swollen poly(styrene-divinylbenzene) with n-butyllithium to form an intermediate in the preparation and halogenation of silylated polystyrene. Bates et al., Macromolecules, 14, (1981), pp. 881-883 discloses the treatment of a divinylbenzene gel with n-butyllithium to detect the presence of vinyl groups in the gel.
However, none of the above references teaches purifying fluids of acidic and oxidant impurities by contacting the fluids with a scavenger containing the pendant functional group disclosed herein and having a macroreticulate structure which provides internal reactive sites. Furthermore, none of these references teaches purifying fluids by contacting with a macroreticulate polymer scavenger having a sufficiently large surface area to effectively purify liquids which do not swell the polymer, and gases.